Why did the United States increase military spending under the presidency of Ronald Reagan?

Ronald Reagan persuaded Congress to fund many of the weapons systems later used in both Persian Gulf wars, either initiating the arms programs or accelerating work on those already in development.

Explanation:

Reagan presided over the biggest peacetime defense buildup in history, from high-tech weapons systems to larger training ranges and military pay increases. "It was his steady focus on the military, said supporters and analysts, that helped bring down the Soviet Union and expunge the malaise and hollowness that infected the American military during the 1970s."

north atlantic treaty organization.